Chapter 5: Electromagnetic Waves — Online MCQ Test
PHYSICS · CLASS 12th · Tamil Nadu State Board
Practice Chapter 5: Electromagnetic Waves with a free chapter-wise online MCQ test.
This chapter covers: This chapter introduces displacement current Maxwell equations and electromagnetic spectrum characteristics. Students explore properties applications and wave propagation modes for....
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Chapter 5: Electromagnetic Waves — Important Questions & Answers
Which one of the following is the correct relationship between the speed of electromagnetic waves in vacuum and the speed of light?
- A. They are different
- B. They are the same
- C. Electromagnetic waves travel slower than light
- D. Electromagnetic waves do not travel in vacuum
Answer: B. They are the same
Electromagnetic waves travel in vacuum with speed equal to the speed of light, c = 3 × 10^8 m s^-1.
Electromagnetic waves travel in vacuum with speed equal to the speed of light, c = 3 × 10^8 m s^-1.
The displacement current introduced by Maxwell is associated with:
- A. A changing magnetic field only
- B. A constant electric field only
- C. A changing electric field
- D. The motion of electrons in a wire only
Answer: C. A changing electric field
Displacement current arises due to a time-varying electric field, even in regions where no conduction current exists.
Displacement current arises due to a time-varying electric field, even in regions where no conduction current exists.
Maxwell’s displacement current term was introduced mainly to make which law consistent?
- A. Faraday’s law
- B. Coulomb’s law
- C. Ampere’s circuital law
- D. Ohm’s law
Answer: C. Ampere’s circuital law
The displacement current term modifies Ampere’s law so that it remains valid for time-varying electric fields.
The displacement current term modifies Ampere’s law so that it remains valid for time-varying electric fields.
Which statement correctly compares radio waves and gamma rays?
- A. Radio waves have higher frequency than gamma rays
- B. Gamma rays have longer wavelength than radio waves
- C. Radio waves have lower frequency and longer wavelength than gamma rays
- D. Both have the same frequency but different amplitudes
Answer: C. Radio waves have lower frequency and longer wavelength than gamma rays
Radio waves occupy the low-frequency, long-wavelength end of the spectrum, while gamma rays are at the high-frequency, short-wavelength end.
Radio waves occupy the low-frequency, long-wavelength end of the spectrum, while gamma rays are at the high-frequency, short-wavelength end.
Which one of the following is the correct order of the electromagnetic spectrum from lower to higher frequency?
- A. Gamma rays, X-rays, ultraviolet, visible, infrared
- B. Infrared, visible, ultraviolet, X-rays, gamma rays
- C. Visible, infrared, ultraviolet, gamma rays, X-rays
- D. Radio waves, gamma rays, microwaves, infrared, visible
Answer: B. Infrared, visible, ultraviolet, X-rays, gamma rays
Frequency increases in the order infrared → visible → ultraviolet → X-rays → gamma rays.
Frequency increases in the order infrared → visible → ultraviolet → X-rays → gamma rays.